Dotter attachment



June 27, 1933. E, R 3 co r AL 1,915,291

DOTTER ATTACHMENT Filed Dec. 23, 1930 WILLI A g S E DY JR A flak 5.8m

FIGZ

FIG. I

BYKWM ATTORNEY Patented June 27, 1933 UNITED" STATES PATENT, OFFICE Enid RALPHlGI-IARLES 'COE, or SUMMIT, AND WILLIAM F. CASSEZDY, or, MILBUR'N,

JERSEY, ASSIGNORS TO INTERNATIONAL COMMUNICATIONS LABORATORIES INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK DOTTER ATTACEMENT "Application filed December 23, 1930. Serial No. 504,280.

eitheralternately positive and negative, or.

else of one polarity followed by aninterval of no current. A more recent method isthatof causing a transmitting relay, under the control of a vibrating relay, to send the'impulses to the line. v

art, that for ease in obtaining a closer balance, the impulses sent to line should be equal in duration, and further that the'duration of a single impulse should be equal to that of the'shortest signal sent out under operating conditions.

, The methods mentioncdabove have been i found. unsatisfactory in' view of the speed at which duplex systems are now operated, and

duejto the varying length of the impulses sent out. p I

For the sake of brevity, and in conform ty with current nomenclature in the telegraph ar-t, .such impulses' will be referred to hereinafter as alternating current or A. (3., t being understood that when such reference is made it may meaneither alternate positive and negative impulses of equal duration, or impulses of one polarity alternating with no current intervals equal in duration to the current impulses.

The principal object of this invention therefore, is to provide a device which may be attached to a sending mechanism such as a tape-transmitter, a keyboard-transmitter, or a printer embodying a transmitter, for transmitting A. C. forbalancing purposes.

A further objectiof thisinvention is to provide a mechanism which will transmit alternating current impulses of unvarying length for balancing purposes.

A. further object is to provide a-device which maybe easily cut in and out of the circuit by some convenient means.

tively connected to the brushes of the device i which will connect the line or local circuit through the device when the latter is placed in operation and which will short circuit the device when the latter is rendered inopera tivea v g i it clearer conception of the operation, construction and further objects of the invention may be had from the followingspecification "taken in conjunction with the accompanying drawing in which:

Figure 1 discloses a front view of the device; r Figure 2 is an end view of Figure 1; It is well understood by those versed 1n the Figure 3 1s a top view of F lgurc 1;

printer;

in use in a duplex telegraph circuit; Figure 6is a schematic view of a modified device in use in a duplex telegraph circuit.

The device comprises a base 1 on which is rotatably mounted a commutator comprising an inner solid ring 2 and an outer ring consisting of segments 3 and at secured to a bakelite disc 10. Segments 3 of the outer ring are strapped to ring 2 by straps 9.

a The commutator is secured to a shaft 5 journalcd in two upright arms 6 and 7 secured to.

the base. Oil cups 8 are provided for lubrieating the shaft bearings. Arm 7' is provided with a portion extending above-arm 6 to providea bearing for one end of a smaller shaft 11. Theother end of. said shaft extends through an arm 12 formed as'shown in Figures 1 and 4. Securedto shaft 11 by adjusted relation with the shaft by athumb .nut 26. r I A furtherobject is to provide a switch ac- The arm carries a spring 27 and a Washer Figure 5 is a schematic view of the device which co-operate with a bracket 29130 form a positioning device and stop for the shaft 11, brushes 16 and 17 and switch 20. Secured to the switch guard 21 as shown in Figures 3 and 4 is a rod 30which'is' adapted to move the brushes 16 and 17 in and out of contact with the commutator and also tip.

the mercury, switch. v

A gear 3.1i's secured to the end of shaft 5,

a" set screw. 32. Thisg' r is adapted to mesh with a'worm 83 secured to the'drive' shaftof the'p'rinter. As long as the printer is in operation, the commutator is rotated,

but A. C. is sent out onthe line only when the brushes are brought into contact with thecommutatorthrough-the movement of igure 5 is 'a schematic showing of the device as used in a duplex telegraph circuit in which 40' designates the line and 41 s a polarized relay having twowindings, name- 1y, an operating winding 42-and a biasing winding 43. Thesqu'are 44 designates the 3 and 4'for th'e'conimutator segments,16 and l'itor the brushes, and QOforthe mercury When the operator desires to transmit Ai C. to obtain a bala'nce,the rod 30 is manipulated,

movingthe brushes '16 and 17into contact 7 with the commutator andi itipping the mercuryswit'ch- 20 to= the position in which the mercury is out of contact with the electrodes. Positive batteryfrom "the. transmitter 44 passes through brush 17, solid ring 2, segments 8,-brush 16 to ground through'the winding 42 of relayx41, thereby moving the armature 45 to the'left and sending negative current out over line '40. hen the brush 16 reaches segment" 4- which isnot strapped to solid ring 3, the circuit through 'winding42 is opened and-the biasing winding 43' 'moves the armature toithe right, thusconnecting positive current; to the line. The armature of relay il-therefore changes position each time that brush '16 passes froma live segment 3 to a dead segment'4 or vice versa,

thereby causing A. Cuto be transmitted to line at afrequency controlled by the rateof rotationof the commutator.

Withtheswitch 20 in the position of Figure 2, the'mercury 45 is lodged inthe left hand end of thetube away from the'electrodes. Howeve'r,fwhen the brushes'16 and '17 are meved out of contact with the commutator, the switch is tipped 1n the opposite'dimotion-and the mercury moves to the right Thefgear 31; meshes with the additional solid ring 51 which is connected to the segments 4.

By. :connectingline 40 to brush 16, positive battery to brush 17 and negativebattery to brush 50 the devicemay' beused to send A. G; direct to linewithout the intervention ofthe transmitting relay. In such case the mercury switch 20 would connect the line to transmitter 44 when the brushes were'moved out of engagement with the commutator. WVhat is claimed is 1 1.- The'co bination of a line circuit, a

transmitting mechanism for connecting'signaling impulsestosaid-line, a-"c'omin'on motor for operatingsaid mechanism, and apparatus for applying alternating current to said line,

' and means for automatically connecting said transmitting mechanism to"'said--line when said'apparatus is inoperative. transmitting apparatus. Like numerals have been used for like parts of the dev1ce,namely- 2; The combination of a line circuit mechanism for transmitting signaling impulses to said'lin'e circuit, a continuously operating commutatonassociated with said mechanism for applying alternating current to said line, a plurality of brushes normally in contact with said commutator and a switch associated therewith for short circuiting said brushes when not iiiacontact with said commutatorfor discontinuing the application of alternatlng current to said line and for'causing the signaling impulses to be connected to said line;

The combination of a line circuit, a; transmitting mechanism and a polarized relay for connecting signaling current to said line, afcircuit' interrupter between "said mechamsm and I said "relay, means for rendering said interrupter" operative to cause'sai'd relay to transmit alternating current over said line and means for making said interrupter inoperative when said transmitting mecha- I11SII11S1I1I1SG.""" i v -4. The combination of a linecircuit, a transmitting'mechanism and a polarized 'relay forcausmg impulses to be transmitted over said line,;'a circuit interrupter between said mechanism and said relay, said interrupter comprlsing a commutator driven by said transmitting mechanism, a plurality of brushes adapted to contact with saidcomm tator for causing said relay to transmit alternating current overfsaid' line and a mercur switch for short-circuiting said brushes when -sa1d transmitting mechanism is in' use to line, a continuously operating commutator associated with said mechanism, a plurality of brushes associated with said commutator,

and adapted to be moved into and out of contact with said commutator, and a mercury switch adapted to automatically disconnect said transmitting mechanism from said line when said brushes are moved into contact with said commutator and to connect said mechanism to said line when said brushes are moved out of contact with said commutator.

7. The combination of a line circuit, mechanism for transmitting signalling impulses to said line, apparatus for applying alternating current to sa1d l1ne, means for automatically preventing said apparatus from applying alternating current to said line when said mechanism is transmitting signalling impulses to said line.

8. The combination of a line circuit, a mechanism and a polarized relay controlled thereby for connecting signalling impulses to said line circuit, an interrupter interposed between said mechanism and polarized relay, means controlled by said interrupter for also operating said relay to connect alternating current to said line circuit, and'means controlled by said mechanismfor preventing said interrupter from operating said polarized relay to connect alternating current to said line circuit.

9. In a device of the class described, the

combination of a printer and an interrupter,

said interrupter comprising a commutator and a plurality of brushes normally in contact therewith, means for short-circuiting said brushes when they are notin contact with said commutator.

'10. The combination of a line circuit, mechanism for transmitting signalling impulses to said line, apparatus for applying alternating current to said line, means for automatically preventing said apparatus from applying alternating current to said line when said mechanism is transmitting signalling impulses to said line, and a motor common to said printer and interrupter for causing their operation.

11. In a device of the class described, the combination of a printer for transmitting signal impulses, an interrupter for transmitting alternating current impulses, acommon motor for operating said printer and sa d interrupter, means to prevent the transm ssion of alternating current impulses by sa d interrupter when signal impulses are being transmitted by said printer.

In witness whereof, we hereby subscribe our names this 15th day of December, 1930.

ERIC R. C. COE. WILLIAM F. CASSEDY', JR. 

